softspi.h

#define MOSI_PIN 7  // teensy 3.1 alt spi pins, change according to your platform.
#define SCK_PIN 14

// Api of this header.
void spi_send(uint8_t data);


// Implementation details...

// template<uint8_t MisoPin, uint8_t MosiPin, uint8_t SckPin, uint8_t Mode = 0>
// class SoftSPI {
//  public:
//   void begin();  // Initialize SoftSPI pins.
//   uint8_t receive();
//   void send(uint8_t data);
//   uint8_t transfer(uint8_t txData);
// };







#include <Arduino.h>
#ifdef __arm__
#ifdef CORE_TEENSY
//------------------------------------------------------------------------------
/** read pin value
 * @param[in] pin Arduino pin number
 * @return value read
 */
static inline __attribute__((always_inline))
bool fastDigitalRead(uint8_t pin) {
  return *portInputRegister(pin);
}
//------------------------------------------------------------------------------
/** Set pin value
 * @param[in] pin Arduino pin number
 * @param[in] level value to write
 */
static inline __attribute__((always_inline))
void fastDigitalWrite(uint8_t pin, bool value) {
	if (value) {
		*portSetRegister(pin) = 1;
	} else {
		*portClearRegister(pin) = 1;
	}
}
#else  // CORE_TEENSY
//------------------------------------------------------------------------------
/** read pin value
 * @param[in] pin Arduino pin number
 * @return value read
 */
static inline __attribute__((always_inline))
bool fastDigitalRead(uint8_t pin){
  return g_APinDescription[pin].pPort->PIO_PDSR & g_APinDescription[pin].ulPin;
}
//------------------------------------------------------------------------------
/** Set pin value
 * @param[in] pin Arduino pin number
 * @param[in] level value to write
 */
static inline __attribute__((always_inline))
void fastDigitalWrite(uint8_t pin, bool value){
  if(value) {
    g_APinDescription[pin].pPort->PIO_SODR = g_APinDescription[pin].ulPin;
  } else {
    g_APinDescription[pin].pPort->PIO_CODR = g_APinDescription[pin].ulPin;
  }
}
#endif  // CORE_TEENSY
//------------------------------------------------------------------------------
inline void fastDigitalToggle(uint8_t pin) {
 fastDigitalWrite(pin, !fastDigitalRead(pin));
 }
//------------------------------------------------------------------------------
inline void fastPinMode(uint8_t pin, bool mode) {pinMode(pin, mode);}
#else  // __arm__
#include <avr/io.h>
#include <util/atomic.h>
//------------------------------------------------------------------------------
/**
 * @class pin_map_t
 * @brief struct for mapping digital pins
 */
struct pin_map_t {
  volatile uint8_t* ddr;   /**< address of DDR for this pin */
  volatile uint8_t* pin;   /**< address of PIN for this pin */
  volatile uint8_t* port;  /**< address of PORT for this pin */
  uint8_t bit;             /**< bit number for this pin */
};
//------------------------------------------------------------------------------
#if defined(__AVR_ATmega168__)\
||defined(__AVR_ATmega168P__)\
||defined(__AVR_ATmega328P__)
// 168 and 328 Arduinos
const static pin_map_t pinMap[] = {
  {&DDRD, &PIND, &PORTD, 0},  // D0  0
  {&DDRD, &PIND, &PORTD, 1},  // D1  1
  {&DDRD, &PIND, &PORTD, 2},  // D2  2
  {&DDRD, &PIND, &PORTD, 3},  // D3  3
  {&DDRD, &PIND, &PORTD, 4},  // D4  4
  {&DDRD, &PIND, &PORTD, 5},  // D5  5
  {&DDRD, &PIND, &PORTD, 6},  // D6  6
  {&DDRD, &PIND, &PORTD, 7},  // D7  7
  {&DDRB, &PINB, &PORTB, 0},  // B0  8
  {&DDRB, &PINB, &PORTB, 1},  // B1  9
  {&DDRB, &PINB, &PORTB, 2},  // B2 10
  {&DDRB, &PINB, &PORTB, 3},  // B3 11
  {&DDRB, &PINB, &PORTB, 4},  // B4 12
  {&DDRB, &PINB, &PORTB, 5},  // B5 13
  {&DDRC, &PINC, &PORTC, 0},  // C0 14
  {&DDRC, &PINC, &PORTC, 1},  // C1 15
  {&DDRC, &PINC, &PORTC, 2},  // C2 16
  {&DDRC, &PINC, &PORTC, 3},  // C3 17
  {&DDRC, &PINC, &PORTC, 4},  // C4 18
  {&DDRC, &PINC, &PORTC, 5}   // C5 19
};
//------------------------------------------------------------------------------
#elif defined(__AVR_ATmega1280__)\
|| defined(__AVR_ATmega2560__)
// Mega
static const pin_map_t pinMap[] = {
  {&DDRE, &PINE, &PORTE, 0},  // E0  0
  {&DDRE, &PINE, &PORTE, 1},  // E1  1
  {&DDRE, &PINE, &PORTE, 4},  // E4  2
  {&DDRE, &PINE, &PORTE, 5},  // E5  3
  {&DDRG, &PING, &PORTG, 5},  // G5  4
  {&DDRE, &PINE, &PORTE, 3},  // E3  5
  {&DDRH, &PINH, &PORTH, 3},  // H3  6
  {&DDRH, &PINH, &PORTH, 4},  // H4  7
  {&DDRH, &PINH, &PORTH, 5},  // H5  8
  {&DDRH, &PINH, &PORTH, 6},  // H6  9
  {&DDRB, &PINB, &PORTB, 4},  // B4 10
  {&DDRB, &PINB, &PORTB, 5},  // B5 11
  {&DDRB, &PINB, &PORTB, 6},  // B6 12
  {&DDRB, &PINB, &PORTB, 7},  // B7 13
  {&DDRJ, &PINJ, &PORTJ, 1},  // J1 14
  {&DDRJ, &PINJ, &PORTJ, 0},  // J0 15
  {&DDRH, &PINH, &PORTH, 1},  // H1 16
  {&DDRH, &PINH, &PORTH, 0},  // H0 17
  {&DDRD, &PIND, &PORTD, 3},  // D3 18
  {&DDRD, &PIND, &PORTD, 2},  // D2 19
  {&DDRD, &PIND, &PORTD, 1},  // D1 20
  {&DDRD, &PIND, &PORTD, 0},  // D0 21
  {&DDRA, &PINA, &PORTA, 0},  // A0 22
  {&DDRA, &PINA, &PORTA, 1},  // A1 23
  {&DDRA, &PINA, &PORTA, 2},  // A2 24
  {&DDRA, &PINA, &PORTA, 3},  // A3 25
  {&DDRA, &PINA, &PORTA, 4},  // A4 26
  {&DDRA, &PINA, &PORTA, 5},  // A5 27
  {&DDRA, &PINA, &PORTA, 6},  // A6 28
  {&DDRA, &PINA, &PORTA, 7},  // A7 29
  {&DDRC, &PINC, &PORTC, 7},  // C7 30
  {&DDRC, &PINC, &PORTC, 6},  // C6 31
  {&DDRC, &PINC, &PORTC, 5},  // C5 32
  {&DDRC, &PINC, &PORTC, 4},  // C4 33
  {&DDRC, &PINC, &PORTC, 3},  // C3 34
  {&DDRC, &PINC, &PORTC, 2},  // C2 35
  {&DDRC, &PINC, &PORTC, 1},  // C1 36
  {&DDRC, &PINC, &PORTC, 0},  // C0 37
  {&DDRD, &PIND, &PORTD, 7},  // D7 38
  {&DDRG, &PING, &PORTG, 2},  // G2 39
  {&DDRG, &PING, &PORTG, 1},  // G1 40
  {&DDRG, &PING, &PORTG, 0},  // G0 41
  {&DDRL, &PINL, &PORTL, 7},  // L7 42
  {&DDRL, &PINL, &PORTL, 6},  // L6 43
  {&DDRL, &PINL, &PORTL, 5},  // L5 44
  {&DDRL, &PINL, &PORTL, 4},  // L4 45
  {&DDRL, &PINL, &PORTL, 3},  // L3 46
  {&DDRL, &PINL, &PORTL, 2},  // L2 47
  {&DDRL, &PINL, &PORTL, 1},  // L1 48
  {&DDRL, &PINL, &PORTL, 0},  // L0 49
  {&DDRB, &PINB, &PORTB, 3},  // B3 50
  {&DDRB, &PINB, &PORTB, 2},  // B2 51
  {&DDRB, &PINB, &PORTB, 1},  // B1 52
  {&DDRB, &PINB, &PORTB, 0},  // B0 53
  {&DDRF, &PINF, &PORTF, 0},  // F0 54
  {&DDRF, &PINF, &PORTF, 1},  // F1 55
  {&DDRF, &PINF, &PORTF, 2},  // F2 56
  {&DDRF, &PINF, &PORTF, 3},  // F3 57
  {&DDRF, &PINF, &PORTF, 4},  // F4 58
  {&DDRF, &PINF, &PORTF, 5},  // F5 59
  {&DDRF, &PINF, &PORTF, 6},  // F6 60
  {&DDRF, &PINF, &PORTF, 7},  // F7 61
  {&DDRK, &PINK, &PORTK, 0},  // K0 62
  {&DDRK, &PINK, &PORTK, 1},  // K1 63
  {&DDRK, &PINK, &PORTK, 2},  // K2 64
  {&DDRK, &PINK, &PORTK, 3},  // K3 65
  {&DDRK, &PINK, &PORTK, 4},  // K4 66
  {&DDRK, &PINK, &PORTK, 5},  // K5 67
  {&DDRK, &PINK, &PORTK, 6},  // K6 68
  {&DDRK, &PINK, &PORTK, 7}   // K7 69
};
//------------------------------------------------------------------------------
#elif defined(__AVR_ATmega1284P__)\
|| defined(__AVR_ATmega1284__)\
|| defined(__AVR_ATmega644P__)\
|| defined(__AVR_ATmega644__)\
|| defined(__AVR_ATmega64__)\
|| defined(__AVR_ATmega32__)\
|| defined(__AVR_ATmega324__)\
|| defined(__AVR_ATmega16__)

#ifdef defined(VARIANT_MIGHTY)
// Mighty Layout
static const pin_map_t pinMap[] = {
  {&DDRB, &PINB, &PORTB, 0},  // B0  0
  {&DDRB, &PINB, &PORTB, 1},  // B1  1
  {&DDRB, &PINB, &PORTB, 2},  // B2  2
  {&DDRB, &PINB, &PORTB, 3},  // B3  3
  {&DDRB, &PINB, &PORTB, 4},  // B4  4
  {&DDRB, &PINB, &PORTB, 5},  // B5  5
  {&DDRB, &PINB, &PORTB, 6},  // B6  6
  {&DDRB, &PINB, &PORTB, 7},  // B7  7
  {&DDRD, &PIND, &PORTD, 0},  // D0  8
  {&DDRD, &PIND, &PORTD, 1},  // D1  9
  {&DDRD, &PIND, &PORTD, 2},  // D2 10
  {&DDRD, &PIND, &PORTD, 3},  // D3 11
  {&DDRD, &PIND, &PORTD, 4},  // D4 12
  {&DDRD, &PIND, &PORTD, 5},  // D5 13
  {&DDRD, &PIND, &PORTD, 6},  // D6 14
  {&DDRD, &PIND, &PORTD, 7},  // D7 15
  {&DDRC, &PINC, &PORTC, 0},  // C0 16
  {&DDRC, &PINC, &PORTC, 1},  // C1 17
  {&DDRC, &PINC, &PORTC, 2},  // C2 18
  {&DDRC, &PINC, &PORTC, 3},  // C3 19
  {&DDRC, &PINC, &PORTC, 4},  // C4 20
  {&DDRC, &PINC, &PORTC, 5},  // C5 21
  {&DDRC, &PINC, &PORTC, 6},  // C6 22
  {&DDRC, &PINC, &PORTC, 7},  // C7 23
  {&DDRA, &PINA, &PORTA, 0},  // A0 24
  {&DDRA, &PINA, &PORTA, 1},  // A1 25
  {&DDRA, &PINA, &PORTA, 2},  // A2 26
  {&DDRA, &PINA, &PORTA, 3},  // A3 27
  {&DDRA, &PINA, &PORTA, 4},  // A4 28
  {&DDRA, &PINA, &PORTA, 5},  // A5 29
  {&DDRA, &PINA, &PORTA, 6},  // A6 30
  {&DDRA, &PINA, &PORTA, 7}   // A7 31
};
#elif defined(VARIANT_BOBUINO)
// Bobuino Layout
static const pin_map_t pinMap[] = {
  {&DDRD, &PIND, &PORTD, 0},  // D0  0
  {&DDRD, &PIND, &PORTD, 1},  // D1  1
  {&DDRD, &PIND, &PORTD, 2},  // D2  2
  {&DDRD, &PIND, &PORTD, 3},  // D3  3
  {&DDRB, &PINB, &PORTB, 0},  // B0  4
  {&DDRB, &PINB, &PORTB, 1},  // B1  5
  {&DDRB, &PINB, &PORTB, 2},  // B2  6
  {&DDRB, &PINB, &PORTB, 3},  // B3  7
  {&DDRD, &PIND, &PORTD, 5},  // D5  8
  {&DDRD, &PIND, &PORTD, 6},  // D6  9
  {&DDRB, &PINB, &PORTB, 4},  // B4 10
  {&DDRB, &PINB, &PORTB, 5},  // B5 11
  {&DDRB, &PINB, &PORTB, 6},  // B6 12
  {&DDRB, &PINB, &PORTB, 7},  // B7 13
  {&DDRA, &PINA, &PORTA, 7},  // A7 14
  {&DDRA, &PINA, &PORTA, 6},  // A6 15
  {&DDRA, &PINA, &PORTA, 5},  // A5 16
  {&DDRA, &PINA, &PORTA, 4},  // A4 17
  {&DDRA, &PINA, &PORTA, 3},  // A3 18
  {&DDRA, &PINA, &PORTA, 2},  // A2 19
  {&DDRA, &PINA, &PORTA, 1},  // A1 20
  {&DDRA, &PINA, &PORTA, 0},  // A0 21
  {&DDRC, &PINC, &PORTC, 0},  // C0 22
  {&DDRC, &PINC, &PORTC, 1},  // C1 23
  {&DDRC, &PINC, &PORTC, 2},  // C2 24
  {&DDRC, &PINC, &PORTC, 3},  // C3 25
  {&DDRC, &PINC, &PORTC, 4},  // C4 26
  {&DDRC, &PINC, &PORTC, 5},  // C5 27
  {&DDRC, &PINC, &PORTC, 6},  // C6 28
  {&DDRC, &PINC, &PORTC, 7},  // C7 29
  {&DDRD, &PIND, &PORTD, 4},  // D4 30
  {&DDRD, &PIND, &PORTD, 7}   // D7 31
};
#elif defined(VARIANT_STANDARD)
// Standard Layout
static const pin_map_t pinMap[] = {
  {&DDRB, &PINB, &PORTB, 0},  // B0  0
  {&DDRB, &PINB, &PORTB, 1},  // B1  1
  {&DDRB, &PINB, &PORTB, 2},  // B2  2
  {&DDRB, &PINB, &PORTB, 3},  // B3  3
  {&DDRB, &PINB, &PORTB, 4},  // B4  4
  {&DDRB, &PINB, &PORTB, 5},  // B5  5
  {&DDRB, &PINB, &PORTB, 6},  // B6  6
  {&DDRB, &PINB, &PORTB, 7},  // B7  7
  {&DDRD, &PIND, &PORTD, 0},  // D0  8
  {&DDRD, &PIND, &PORTD, 1},  // D1  9
  {&DDRD, &PIND, &PORTD, 2},  // D2 10
  {&DDRD, &PIND, &PORTD, 3},  // D3 11
  {&DDRD, &PIND, &PORTD, 4},  // D4 12
  {&DDRD, &PIND, &PORTD, 5},  // D5 13
  {&DDRD, &PIND, &PORTD, 6},  // D6 14
  {&DDRD, &PIND, &PORTD, 7},  // D7 15
  {&DDRC, &PINC, &PORTC, 0},  // C0 16
  {&DDRC, &PINC, &PORTC, 1},  // C1 17
  {&DDRC, &PINC, &PORTC, 2},  // C2 18
  {&DDRC, &PINC, &PORTC, 3},  // C3 19
  {&DDRC, &PINC, &PORTC, 4},  // C4 20
  {&DDRC, &PINC, &PORTC, 5},  // C5 21
  {&DDRC, &PINC, &PORTC, 6},  // C6 22
  {&DDRC, &PINC, &PORTC, 7},  // C7 23
  {&DDRA, &PINA, &PORTA, 7},  // A7 24
  {&DDRA, &PINA, &PORTA, 6},  // A6 25
  {&DDRA, &PINA, &PORTA, 5},  // A5 26
  {&DDRA, &PINA, &PORTA, 4},  // A4 27
  {&DDRA, &PINA, &PORTA, 3},  // A3 28
  {&DDRA, &PINA, &PORTA, 2},  // A2 29
  {&DDRA, &PINA, &PORTA, 1},  // A1 30
  {&DDRA, &PINA, &PORTA, 0}   // A0 31
};
#else  // VARIANT_MIGHTY
#error Undefined variant 1284, 644, 324, 64, 32
#endif  // VARIANT_MIGHTY
//------------------------------------------------------------------------------
#elif defined(__AVR_ATmega32U4__)
#ifdef CORE_TEENSY
// Teensy 2.0
static const pin_map_t pinMap[] = {
  {&DDRB, &PINB, &PORTB, 0},  // B0  0
  {&DDRB, &PINB, &PORTB, 1},  // B1  1
  {&DDRB, &PINB, &PORTB, 2},  // B2  2
  {&DDRB, &PINB, &PORTB, 3},  // B3  3
  {&DDRB, &PINB, &PORTB, 7},  // B7  4
  {&DDRD, &PIND, &PORTD, 0},  // D0  5
  {&DDRD, &PIND, &PORTD, 1},  // D1  6
  {&DDRD, &PIND, &PORTD, 2},  // D2  7
  {&DDRD, &PIND, &PORTD, 3},  // D3  8
  {&DDRC, &PINC, &PORTC, 6},  // C6  9
  {&DDRC, &PINC, &PORTC, 7},  // C7 10
  {&DDRD, &PIND, &PORTD, 6},  // D6 11
  {&DDRD, &PIND, &PORTD, 7},  // D7 12
  {&DDRB, &PINB, &PORTB, 4},  // B4 13
  {&DDRB, &PINB, &PORTB, 5},  // B5 14
  {&DDRB, &PINB, &PORTB, 6},  // B6 15
  {&DDRF, &PINF, &PORTF, 7},  // F7 16
  {&DDRF, &PINF, &PORTF, 6},  // F6 17
  {&DDRF, &PINF, &PORTF, 5},  // F5 18
  {&DDRF, &PINF, &PORTF, 4},  // F4 19
  {&DDRF, &PINF, &PORTF, 1},  // F1 20
  {&DDRF, &PINF, &PORTF, 0},  // F0 21
  {&DDRD, &PIND, &PORTD, 4},  // D4 22
  {&DDRD, &PIND, &PORTD, 5},  // D5 23
  {&DDRE, &PINE, &PORTE, 6}   // E6 24
};
//------------------------------------------------------------------------------
#else  // CORE_TEENSY
// Leonardo
static const pin_map_t pinMap[] = {
  {&DDRD, &PIND, &PORTD, 2},  // D2  0
  {&DDRD, &PIND, &PORTD, 3},  // D3  1
  {&DDRD, &PIND, &PORTD, 1},  // D1  2
  {&DDRD, &PIND, &PORTD, 0},  // D0  3
  {&DDRD, &PIND, &PORTD, 4},  // D4  4
  {&DDRC, &PINC, &PORTC, 6},  // C6  5
  {&DDRD, &PIND, &PORTD, 7},  // D7  6
  {&DDRE, &PINE, &PORTE, 6},  // E6  7
  {&DDRB, &PINB, &PORTB, 4},  // B4  8
  {&DDRB, &PINB, &PORTB, 5},  // B5  9
  {&DDRB, &PINB, &PORTB, 6},  // B6 10
  {&DDRB, &PINB, &PORTB, 7},  // B7 11
  {&DDRD, &PIND, &PORTD, 6},  // D6 12
  {&DDRC, &PINC, &PORTC, 7},  // C7 13
  {&DDRB, &PINB, &PORTB, 3},  // B3 14
  {&DDRB, &PINB, &PORTB, 1},  // B1 15
  {&DDRB, &PINB, &PORTB, 2},  // B2 16
  {&DDRB, &PINB, &PORTB, 0},  // B0 17
  {&DDRF, &PINF, &PORTF, 7},  // F7 18
  {&DDRF, &PINF, &PORTF, 6},  // F6 19
  {&DDRF, &PINF, &PORTF, 5},  // F5 20
  {&DDRF, &PINF, &PORTF, 4},  // F4 21
  {&DDRF, &PINF, &PORTF, 1},  // F1 22
  {&DDRF, &PINF, &PORTF, 0},  // F0 23
  {&DDRD, &PIND, &PORTD, 4},  // D4 24
  {&DDRD, &PIND, &PORTD, 7},  // D7 25
  {&DDRB, &PINB, &PORTB, 4},  // B4 26
  {&DDRB, &PINB, &PORTB, 5},  // B5 27
  {&DDRB, &PINB, &PORTB, 6},  // B6 28
  {&DDRD, &PIND, &PORTD, 6}   // D6 29
};
#endif  // CORE_TEENSY
//------------------------------------------------------------------------------
#elif defined(__AVR_AT90USB646__)\
|| defined(__AVR_AT90USB1286__)
// Teensy++ 1.0 & 2.0
static const pin_map_t pinMap[] = {
  {&DDRD, &PIND, &PORTD, 0},  // D0  0
  {&DDRD, &PIND, &PORTD, 1},  // D1  1
  {&DDRD, &PIND, &PORTD, 2},  // D2  2
  {&DDRD, &PIND, &PORTD, 3},  // D3  3
  {&DDRD, &PIND, &PORTD, 4},  // D4  4
  {&DDRD, &PIND, &PORTD, 5},  // D5  5
  {&DDRD, &PIND, &PORTD, 6},  // D6  6
  {&DDRD, &PIND, &PORTD, 7},  // D7  7
  {&DDRE, &PINE, &PORTE, 0},  // E0  8
  {&DDRE, &PINE, &PORTE, 1},  // E1  9
  {&DDRC, &PINC, &PORTC, 0},  // C0 10
  {&DDRC, &PINC, &PORTC, 1},  // C1 11
  {&DDRC, &PINC, &PORTC, 2},  // C2 12
  {&DDRC, &PINC, &PORTC, 3},  // C3 13
  {&DDRC, &PINC, &PORTC, 4},  // C4 14
  {&DDRC, &PINC, &PORTC, 5},  // C5 15
  {&DDRC, &PINC, &PORTC, 6},  // C6 16
  {&DDRC, &PINC, &PORTC, 7},  // C7 17
  {&DDRE, &PINE, &PORTE, 6},  // E6 18
  {&DDRE, &PINE, &PORTE, 7},  // E7 19
  {&DDRB, &PINB, &PORTB, 0},  // B0 20
  {&DDRB, &PINB, &PORTB, 1},  // B1 21
  {&DDRB, &PINB, &PORTB, 2},  // B2 22
  {&DDRB, &PINB, &PORTB, 3},  // B3 23
  {&DDRB, &PINB, &PORTB, 4},  // B4 24
  {&DDRB, &PINB, &PORTB, 5},  // B5 25
  {&DDRB, &PINB, &PORTB, 6},  // B6 26
  {&DDRB, &PINB, &PORTB, 7},  // B7 27
  {&DDRA, &PINA, &PORTA, 0},  // A0 28
  {&DDRA, &PINA, &PORTA, 1},  // A1 29
  {&DDRA, &PINA, &PORTA, 2},  // A2 30
  {&DDRA, &PINA, &PORTA, 3},  // A3 31
  {&DDRA, &PINA, &PORTA, 4},  // A4 32
  {&DDRA, &PINA, &PORTA, 5},  // A5 33
  {&DDRA, &PINA, &PORTA, 6},  // A6 34
  {&DDRA, &PINA, &PORTA, 7},  // A7 35
  {&DDRE, &PINE, &PORTE, 4},  // E4 36
  {&DDRE, &PINE, &PORTE, 5},  // E5 37
  {&DDRF, &PINF, &PORTF, 0},  // F0 38
  {&DDRF, &PINF, &PORTF, 1},  // F1 39
  {&DDRF, &PINF, &PORTF, 2},  // F2 40
  {&DDRF, &PINF, &PORTF, 3},  // F3 41
  {&DDRF, &PINF, &PORTF, 4},  // F4 42
  {&DDRF, &PINF, &PORTF, 5},  // F5 43
  {&DDRF, &PINF, &PORTF, 6},  // F6 44
  {&DDRF, &PINF, &PORTF, 7}   // F7 45
};
//------------------------------------------------------------------------------
#else  // CPU type
#error unknown CPU type
#endif  // CPU type
//------------------------------------------------------------------------------
/** count of pins */
static const uint8_t digitalPinCount = sizeof(pinMap)/sizeof(pin_map_t);
//==============================================================================
/** generate bad pin number error */
void badPinNumber(void)
  __attribute__((error("Pin number is too large or not a constant")));
//------------------------------------------------------------------------------
/** Check for valid pin number
 * @param[in] pin Number of pin to be checked.
 */
static inline __attribute__((always_inline))
void badPinCheck(uint8_t pin) {
  if (!__builtin_constant_p(pin) || pin >= digitalPinCount) {
     badPinNumber();
  }
}
//------------------------------------------------------------------------------
/** fast write helper
 * @param[in] address I/O register address
 * @param[in] bit bit number to write
 * @param[in] level value for bit
 */
static inline __attribute__((always_inline))
void fastBitWriteSafe(volatile uint8_t* address, uint8_t bit, bool level) {
  uint8_t oldSREG;
  if (address > (uint8_t*)0X5F) {
    oldSREG = SREG;
    cli();
  }
  if (level) {
    *address |= 1 << bit;
  } else {
    *address &= ~(1 << bit);
  }
  if (address > (uint8_t*)0X5F) {
    SREG = oldSREG;
  }
}
//------------------------------------------------------------------------------
/** read pin value
 * @param[in] pin Arduino pin number
 * @return value read
 */
static inline __attribute__((always_inline))
bool fastDigitalRead(uint8_t pin) {
  badPinCheck(pin);
  return (*pinMap[pin].pin >> pinMap[pin].bit) & 1;
}
//------------------------------------------------------------------------------
/** toggle a pin
 * @param[in] pin Arduino pin number
 *
 * If the pin is in output mode toggle the pin level.
 * If the pin is in input mode toggle the state of the 20K pullup.
 */
static inline __attribute__((always_inline))
void fastDigitalToggle(uint8_t pin) {
  badPinCheck(pin);
    if (pinMap[pin].pin > (uint8_t*)0X5F) {
      // must write bit to high address port
      *pinMap[pin].pin = 1 << pinMap[pin].bit;
    } else {
      // will compile to sbi and PIN register will not be read.
      *pinMap[pin].pin |= 1 << pinMap[pin].bit;
    }
}
//------------------------------------------------------------------------------
/** Set pin value
 * @param[in] pin Arduino pin number
 * @param[in] level value to write
 */
static inline __attribute__((always_inline))
void fastDigitalWrite(uint8_t pin, bool level) {
  badPinCheck(pin);
  fastBitWriteSafe(pinMap[pin].port, pinMap[pin].bit, level);
}
//------------------------------------------------------------------------------
/** set pin mode
 * @param[in] pin Arduino pin number
 * @param[in] mode if true set output mode else input mode
 *
 * fastPinMode does not enable or disable the 20K pullup for input mode.
 */
static inline __attribute__((always_inline))
void fastPinMode(uint8_t pin, bool mode) {
  badPinCheck(pin);
  fastBitWriteSafe(pinMap[pin].ddr, pinMap[pin].bit, mode);
}

#endif  // __arm__
//------------------------------------------------------------------------------
/** set pin configuration
 * @param[in] pin Arduino pin number
 * @param[in] mode If true set output mode else input mode
 * @param[in] level If mode is output, set level high/low.
 *                  If mode is input, enable or disable the pin's 20K pullup.
 */
static inline __attribute__((always_inline))
void fastPinConfig(uint8_t pin, bool mode, bool level) {
  fastPinMode(pin, mode);
  fastDigitalWrite(pin, level);
}
//==============================================================================
/**
 * @class DigitalPin
 * @brief Fast digital port I/O
 */
template<uint8_t PinNumber>
class DigitalPin {
 public:
  //----------------------------------------------------------------------------
  /** Constructor */
  DigitalPin() {}
  //----------------------------------------------------------------------------
  /** Constructor
   * @param[in] pinMode if true set output mode else input mode.
   */
  explicit DigitalPin(bool pinMode) {
    mode(pinMode);
  }
  //----------------------------------------------------------------------------
  /** Constructor
   * @param[in] mode If true set output mode else input mode
   * @param[in] level If mode is output, set level high/low.
   *                  If mode is input, enable or disable the pin's 20K pullup.
   */
  DigitalPin(bool mode, bool level) {
    config(mode, level);
  }
  //----------------------------------------------------------------------------
  /** Asignment operator
   * @param[in] value If true set the pin's level high else set the
   *  pin's level low.
   *
   * @return This DigitalPin instance.
   */
  inline DigitalPin & operator = (bool value) __attribute__((always_inline)) {
    write(value);
    return *this;
  }
  //----------------------------------------------------------------------------
  /** Parenthesis operator
   * @return Pin's level
   */
	inline operator bool () const __attribute__((always_inline)) {
    return read();
  }
  //----------------------------------------------------------------------------
  /** set pin configuration
   * @param[in] mode If true set output mode else input mode
   * @param[in] level If mode is output, set level high/low.
   *                  If mode is input, enable or disable the pin's 20K pullup.
   */
  inline __attribute__((always_inline))
  void config(bool mode, bool level) {
    fastPinConfig(PinNumber, mode, level);
  }
  //----------------------------------------------------------------------------
  /**
   * Set pin level high if output mode or enable 20K pullup if input mode.
   */
  inline __attribute__((always_inline))
  void high() {write(true);}
  //----------------------------------------------------------------------------
  /**
   * Set pin level low if output mode or disable 20K pullup if input mode.
   */
  inline __attribute__((always_inline))
  void low() {write(false);}
  //----------------------------------------------------------------------------
  /**
   * Set pin mode
   * @param[in] pinMode if true set output mode else input mode.
   *
   * mode() does not enable or disable the 20K pullup for input mode.
   */
  inline __attribute__((always_inline))
  void mode(bool pinMode) {
    fastPinMode(PinNumber, pinMode);
  }
  //----------------------------------------------------------------------------
  /** @return Pin's level */
  inline __attribute__((always_inline))
  bool read() const {
    return fastDigitalRead(PinNumber);
  }
  //----------------------------------------------------------------------------
  /** toggle a pin
   *
   * If the pin is in output mode toggle the pin's level.
   * If the pin is in input mode toggle the state of the 20K pullup.
   */
  inline __attribute__((always_inline))
  void toggle() {
    fastDigitalToggle(PinNumber);
  }
  //----------------------------------------------------------------------------
  /** Write the pin's level.
   * @param[in] value If true set the pin's level high else set the
   *  pin's level low.
   */
  inline __attribute__((always_inline))
  void write(bool value) {
    fastDigitalWrite(PinNumber, value);
  }
};

//------------------------------------------------------------------------------
/** Nop for timing. */
#define nop asm volatile ("nop\n\t")
//------------------------------------------------------------------------------
/** Pin Mode for MISO is input.*/
const bool MISO_MODE  = false;
/** Pullups disabled for MISO are disabled. */
const bool MISO_LEVEL = false;
/** Pin Mode for MOSI is output.*/
const bool MOSI_MODE  = true;
/** Pin Mode for SCK is output. */
const bool SCK_MODE   = true;
//------------------------------------------------------------------------------
/**
 * @class SoftSPI
 * @brief Fast software SPI.
 */
template<uint8_t MisoPin, uint8_t MosiPin, uint8_t SckPin, uint8_t Mode = 0>
class SoftSPI {
 public:
  //----------------------------------------------------------------------------
  /** Initialize SoftSPI pins. */
  void begin() {
    fastPinConfig(MisoPin, MISO_MODE, MISO_LEVEL);
    fastPinConfig(MosiPin, MOSI_MODE, !MODE_CPHA(Mode));
    fastPinConfig(SckPin, SCK_MODE, MODE_CPOL(Mode));
  }
  //----------------------------------------------------------------------------
  /** Soft SPI receive byte.
   * @return Data byte received.
   */
  inline __attribute__((always_inline))
  uint8_t receive() {
    uint8_t data = 0;
    receiveBit(7, &data);
    receiveBit(6, &data);
    receiveBit(5, &data);
    receiveBit(4, &data);
    receiveBit(3, &data);
    receiveBit(2, &data);
    receiveBit(1, &data);
    receiveBit(0, &data);
    return data;
  }
  //----------------------------------------------------------------------------
  /** Soft SPI send byte.
   * @param[in] data Data byte to send.
   */
  inline __attribute__((always_inline))
  void send(uint8_t data) {
    sendBit(7, data);
    sendBit(6, data);
    sendBit(5, data);
    sendBit(4, data);
    sendBit(3, data);
    sendBit(2, data);
    sendBit(1, data);
    sendBit(0, data);
  }
  //----------------------------------------------------------------------------
  /** Soft SPI transfer byte.
   * @param[in] txData Data byte to send.
   * @return Data byte received.
   */
  inline __attribute__((always_inline))
  uint8_t transfer(uint8_t txData) {
    uint8_t rxData = 0;
    transferBit(7, &rxData, txData);
    transferBit(6, &rxData, txData);
    transferBit(5, &rxData, txData);
    transferBit(4, &rxData, txData);
    transferBit(3, &rxData, txData);
    transferBit(2, &rxData, txData);
    transferBit(1, &rxData, txData);
    transferBit(0, &rxData, txData);
    return rxData;
  }

 private:
  //----------------------------------------------------------------------------
  inline __attribute__((always_inline))
  bool MODE_CPHA(uint8_t mode) {return (mode & 1) != 0;}
  inline __attribute__((always_inline))
  bool MODE_CPOL(uint8_t mode) {return (mode & 2) != 0;}
  inline __attribute__((always_inline))
  void receiveBit(uint8_t bit, uint8_t* data) {
    if (MODE_CPHA(Mode)) {
      fastDigitalWrite(SckPin, !MODE_CPOL(Mode));
    }
    nop;
    nop;
    fastDigitalWrite(SckPin,
      MODE_CPHA(Mode) ? MODE_CPOL(Mode) : !MODE_CPOL(Mode));
    if (fastDigitalRead(MisoPin)) *data |= 1 << bit;
    if (!MODE_CPHA(Mode)) {
      fastDigitalWrite(SckPin, MODE_CPOL(Mode));
    }
  }
  //----------------------------------------------------------------------------
  inline __attribute__((always_inline))
  void sendBit(uint8_t bit, uint8_t data) {
    if (MODE_CPHA(Mode)) {
      fastDigitalWrite(SckPin, !MODE_CPOL(Mode));
    }
    fastDigitalWrite(MosiPin, data & (1 << bit));
    fastDigitalWrite(SckPin,
      MODE_CPHA(Mode) ? MODE_CPOL(Mode) : !MODE_CPOL(Mode));
    nop;
    nop;
    if (!MODE_CPHA(Mode)) {
      fastDigitalWrite(SckPin, MODE_CPOL(Mode));
    }
  }
  //----------------------------------------------------------------------------
  inline __attribute__((always_inline))
  void transferBit(uint8_t bit, uint8_t* rxData, uint8_t txData) {
    if (MODE_CPHA(Mode)) {
      fastDigitalWrite(SckPin, !MODE_CPOL(Mode));
    }
    fastDigitalWrite(MosiPin, txData & (1 << bit));
    fastDigitalWrite(SckPin,
      MODE_CPHA(Mode) ? MODE_CPOL(Mode) : !MODE_CPOL(Mode));
    if (fastDigitalRead(MisoPin)) *rxData |= 1 << bit;
    if (!MODE_CPHA(Mode)) {
      fastDigitalWrite(SckPin, MODE_CPOL(Mode));
    }
  }
  //----------------------------------------------------------------------------
};



void spi_send(uint8_t data) {
  static SoftSPI<23, MOSI_PIN, SCK_PIN> softSpi;
  static bool initialized = false;
  if (!initialized) {
    initialized = true;
    softSpi.begin();
  }
  softSpi.send(data);
}